In-Class Exercise 4

In this in-class exercise, I will learn how to apply spatial point analysis techniques

Niharika Avula https://example.com/norajones
2021-09-09

R Packages

The following five R Packages are used * sf is mainly used for importing geospatial data * Maptools is used to convert spatial object to ppp format (vector data conversion method) * All output of spatstat is going to be raster grid * sf is specially design for sf layr, raster is specially designed for raster layer

Importing Geospatial Data

sg_sf <- st_read(dsn = "data/shapefile", layer = "CostalOutline")

Reading layer `CostalOutline' from data source 
  `C:\Niharika-avula\IS415_blog\_posts\2021-09-06-in-class-exercise-4\data\shapefile' 
  using driver `ESRI Shapefile'
Simple feature collection with 60 features and 4 fields
Geometry type: POLYGON
Dimension:     XY
Bounding box:  xmin: 2663.926 ymin: 16357.98 xmax: 56047.79 ymax: 50244.03
Projected CRS: SVY21
mpsz_sf <- st_read(dsn = "data/shapefile", layer = "MP14_SUBZONE_WEB_PL")

Reading layer `MP14_SUBZONE_WEB_PL' from data source 
  `C:\Niharika-avula\IS415_blog\_posts\2021-09-06-in-class-exercise-4\data\shapefile' 
  using driver `ESRI Shapefile'
Simple feature collection with 323 features and 15 fields
Geometry type: MULTIPOLYGON
Dimension:     XY
Bounding box:  xmin: 2667.538 ymin: 15748.72 xmax: 56396.44 ymax: 50256.33
Projected CRS: SVY21

Importing Aspatial Data

childcare <- read_rds("data/rds/childcare.rds")
CHAS <- read_rds("data/rds/CHAS.rds")

Converting from apatial to geospatial

CHAS_sf <- st_as_sf(CHAS, 
                    coords = c("X_COORDINATE", 
                               "Y_COORDINATE"), 
                    crs = 3414)

childcare$Lat <- as.numeric(childcare$Lat)
childcare$Lng <- as.numeric(childcare$Lng)
childcare_sf <- st_as_sf(childcare, 
                    coords = c("Lng", 
                               "Lat"), 
                       crs = 4326) %>%
  st_transform(crs = 3414)

Geospatial Data Wrangling

Converting from sf to Spatial* Classes

childcare <- as_Spatial(childcare_sf)
CHAS <- as_Spatial(CHAS_sf)
sg <- as_Spatial(sg_sf)

Converting from Spatial* Classes to sp format

childcare_sp <- as(childcare, "SpatialPoints")
CHAS_sp <- as(CHAS, "SpatialPoints")
SG_sp <- as(sg, "SpatialPolygons")

Converting from sp format to ppp format

childcare_ppp <- as(childcare_sp, "ppp")
CHAS_ppp <- as(CHAS_sp, "ppp")

tmap_mode ('view')
tm_shape(childcare_sf)+
  tm_dots(alpha = 0.4,
          col = "blue",
          size = 0.05) +
  tm_shape(CHAS_sf) +
  tm_dots(alpha = 0.4,
          col = "red",
          size = 0.05)

tmap_mode('plot')